Sometimes your brain plays little tricks like these to you... You can be 100% convinced of something, and in your brain it is "reality", but in fact it is only an "image of reality" and the "objective reality" may be quite different... For this reason, police officers learn to never trust the statements of eye witnesses. You may have seen something red right the moment before or after you have seen the bank robbers escape in their car. Your brain did not persist the color of that car to your permanent memory (because it was busy with something else in that moment), but "you" are not aware of this fact. And when "you" try to access that piece of data at a later time, instead of telling you "sorry, that piece of data is not available", the brain's "auto-correction capabilities" fill in the missing detail from a nearby related "file", i.e. something red that you have seen at that moment and that at that time had been considered "worthy" of being put into the permanent memory.
So you are 100% convinced yourself that you have actually seen the red car -- even though in reality the car was blue!